I've had the Vyper 2 for about one year and like it a lot. It's easy to read and operate. Along with the usual features, it has 2-gas switching (also useful if you strap an Air tank on but forget to change your computer from your last Nitrox mix before hopping in the water), a nice graphical representation of dive profiles in the log book, and a simulator so that you can familiarize yourself with all of the readouts.
I can't speak to the accuracy or service issues reported by others, but the depth readings are more or less consistent with those on my wife's Aladdin Prime (haven't done a side-by-side comparision, but our max is always within a few feet, and that's probably accurate).
On the negative side, the compass is definitely difficult to use and I prefer the regular one on my console for that. The computer is also quite conservative in all the published tests. This was borne out by my experience, where my NDLs are always significantly lower than my wife's, given similar profiles. I also noticed that if you go into deco on one dive, you seem to take a big hit to NDL on the next. Finally, you're supposed to round down Nitrox percentages for the purposes of N2 calculations, while the computer automatically adds 1% to the user setting for O2/MOD calculations.
Hope this helps!